Biosafety Cabinet and Fume Hood Comparison

Safety should be the top priority in any laboratory, and two pieces of equipment that are central to laboratory safety are biosafety cabinets (BSCs) and fume hoods. But although the two may look similar from the outside, and while we often refer to both of them simply as “hoods”, there are fundamental differences between them—and knowing these differences is key to selecting the appropriate enclosure to keep you, and your research, safe.

Levels and types of protection

The main difference between BSCs and fume hoods is what they are intended to protect the operator from, according to Seth De Penning, Product Marketing Manager at NuAire. “Biosafety cabinets are designed to provide personnel protection against airborne biological hazards, whereas fume hoods are designed to provide protection against chemical fumes.”

They also differ in the level of protection they offer. “A fume hood protects the individual handling the material, while a BSC protects the individual, environment, and the material,” adds Anne-Sophie Brocard, Ph.D., Biosafety Officer and EHS Leader at ATCC. So, knowing who or what you need to protect, and what you need the protection from, is crucial to selecting the right equipment for you.

Airflow and filtration

Another key point of comparison is in the operation of BSCs and fume hoods. Each enclosure has airflow specific to the hazard and level of protection for which it was designed.

Fume hoods deliver continuous airflow up and away from the user offering protection from hazardous chemicals. Air is drawn into the hood, across the work area and toward the back of the unit, where it may be treated before being diluted and exiting from the building (if ducted) or recirculated back into the laboratory (ductless). This design means the user could, for example “work with benzene and not be exposed to it,” Brocard explains.

BSCs, by comparison, have vertical, unidirectional downflow airflow within the work area. The main difference to fume hoods however, is the use of high-efficiency particulate air or HEPA filtration. HEPA filters trap harmful particulates and other infectious agents, meaning that only safe microbe-free air is released back into the environment.

Purpose and applications

The applications of fume hoods and BSCs is another point of comparison. Because fume hoods and BSCs are designed to handle different types of materials, they are better suitable for different applications.

The continuous backward airflow of fume hoods mean they are perfect for offering protection against odorous or reactive materials, poisonous gases, carcinogens, or other volatile or toxic materials. They also act as a physical barrier against chemical spills, and base cabinets beneath bench top hoods can offer safe laboratory storage of acids or flammable materials. Because of such safety, fume hoods are commonplace in every research and forensic labs, as well as educational establishments around the world. Because fume hoods only protect the user, they cannot be used when the sterility of your research is a concern. Fume hoods “do not protect the material, meaning an opened agar plate will grow every single fungus and bacteria that is naturally floating in the air,” Brocard says. For this reason, cell culture should not be completed in a fume hood.

There are two main types of fume hoods: ducted and ductless, and as Alex Atmadi, Technical Sales Manager at Esco Technologies, explains, choosing which one is right for you depends on the chemical hazard you are working with. For “naturally evaporating chemicals and handling a limited range or volume” you can opt for a ductless fume hood, Atmadi explains, but ducted fume hoods allow you to handle heated chemicals or a wider range or volume.

By contrast, because BSCs offer protection to both the user and the material, they are suitable for applications where sterility is important—such as in cell culture processing. The HEPA filtration means they are suitable for handling infectious agents or biohazards, and are therefore essential in any work handling viruses, pathogens, genetically modified microorganisms, recombinant DNA, or the clinical preparation of medications and treatments that involve materials hazardous to health.

“Industry guidelines such as the biosafety manuals from the CDC/NIH or the WHO, as well as industry standards such as the NSF/ANSI 49 or EN 12469, assign biosafety cabinets to one of three different classes,” De Penning explains, with classifications indicating the level of protection each provides against biological agents.

Differing only by HEPA filtration, Class I is most similar to a fume hood, and is only suitable for low-level Biosafety Level (BSL-1, 2 or 3) containment. Classes II (of which there are different types A1, A2, B1, B2 or C1) and III offer greater containment; Class III offers the highest level of protection and is essential for any work with risk group level 4 agents.

“Scientists who have good safety produce good science,” emphasizes Brocard, and BSC and fume hoods are two pieces of equipment that are central to ensuring this. Understanding the differences between them, however, is critical in selecting the right enclosure to protect both yourself, and the integrity of your research.

But what’s next for laboratory safety? According to Atmadi, improved energy efficiency to be environmentally friendly and reduce operating costs; comfortable ergonomics, to reduce work fatigue and improve concentration; and connectivity, to remotely monitor the units, all could be future developments.

Fume Hoods vs Biosafety Cabinets